Newly added users not placed in order by Username

Hi,
When I add a new user, the identifier is the username field. All of our users have a alpha-numerical username previously assigned, and are added in random order to Community Builder. I've noticed that when I add a new user randomly, it puts them in the end of the CB list, regardless of their username.

In Joomla!'s User Manager component, I am able to re-sort them by many columns, to include the username field. However, in CB's User Management component, the header fields are greyed-out and I am unable to resort my users.

Is this feature not available in CB?

Regards
Erick

correct - no such feature in CB.